;Make a DM, with 3 actuators, to do tip/tilt only. Numbering starts from top left.

function make_dmtt, posns, psize, m_pix

x = [-1,1,0]/m_pix
y = [.5,.5,-1]/m_pix
x += psize/2
y += psize/2
triangulate, x, y, triangles
dm = trigrid(x,y, posns, triangles, [1,1], [0,0,psize-1,psize-1])
return, dm
end
